Drum Brake (parking brake)

The diagram shows a handbrake which is integrated into a hydraulic drum brake. The spreading nowadays mostly takes place with the help of cables, actuated from the hand brake lever through a mechanical offset. This offset might - as indicated in the picture - be a two-sided lever or a cable guide allowing the reference point to be moved. This way, small differences in clearance between right and left are corrected.
The handbrake cable grasps the expander lever against the force of the spring that wrapes the cable and moves it with a large lever arm to the left. The expander lever is supported by a rod, which is connected to the left brake shoe, ensuring that both brake shoes are being activated. In the rod, a self-adjusting mechanism is insinuated. If the clearance becomes too large, it is being enlarged (in this case there are two).